EXPERIMENTAL STUDY ON TRANSIENT THERMAL PERFORMANCE OF P-CFRP UNDER TENSILE LOADING AND CLOSE-TO-FIRE CONDITION

Abstract

Pultruded carbon fibre reinforced polymer (P-CFRP) is popular used in flexural- strengthening civil engineering structures such as beams, slabs, and walls. When a fire happens, these structures and reinforced materials are simultaneously exposed to both high temperatures (potentially up to 1200°C) and mechanical loadings at the same time. This combined condition is complicated and difficult to be replicated in experimental investigation. Therefore, the studies of CFRP and structure reinforced with CFRP in fire are rare due to expensive cost of experiments and insufficient theoretical calculations. For these reasons, this study aims to investigate the performance of P-CFRP in transient thermal and mechanical conditions that close to fire, regarding the simultaneousness of these effects. In the test condition, the mechanical load is applied on P-CFRP material and then maintained; the temperature surrounding P-CFRP material is then increased with the heating rate up to 30°C/minute until rupture. The P-CFRP specimen has been tested at several mechanical levels corresponding to from 10% to 68% of its ultimate strength at 20°C. The result shows that when the mechanical load increases from 10% to 50% of its ultimate strength at 20°C, the temperature, at which P-CFRP failure, gradually decreases. When the mechanical load increases to 68% of its ultimate strength at 20°C, the failure temperature of P-CFRP significantly reduces. The experimental result also indicates that, as the heating rate increases from 2°C/minute to 26°C/minute, the failure temperature increases up to 14.6%. The obtained result well confirms the combined influence between thermal and mechanical loadings on the performance of P-CFRP at thermo-mechanical conditions, disregarding the sequence of loads. The failure mode of P-CFRP at different studied cases will also be discussed.